A PurpleAir Classic and a PurpleAir Flex air quality monitoring sensor were installed at a monitoring site in East Hartford, Connecticut to evaluate the sensors performance tracking PM2.5 data. PurpleAir data was corrected using the extended U.S-wide correction equation developed by the EPA to reduce bias in sensor data (more information found here: AirNow). Hourly data from 2023 was then compared to a T640 reference monitor located at the same location. The full dataset used can be downloaded here Download CSV.

Sensor Details

PurpleAir Specifications

Sensor Type Cost Differences Possible Configuration Evaluated Configuration Data Access Power Supply Considerations Reference Monitor Compared
PurpleAir Classic Sensor: $229 PM2.5, Temperature, Relative Humidity, Pressure PM2.5, Temperature, Relative Humidity Potted 5V USB outdoor power supply 12 ft mains plug (purchased separately-$40) Micro SD card, WiFi connectivity, API download and live public online map Effected by saltwater (issues with coastal use), Life Expectancy ~2 years, laser counters may need replacements PM2.5: Teledyne API T640X
Temp & RH: AutoMet 580
PurpleAir Flex Sensor: $289 LED light display with AQI color

Setup

PurpleAir Classic (left) and PurpleAir Flex (right) air quality monitor.

PurpleAir Classic (left) and PurpleAir Flex (right) air quality monitor.


Timeseries Comparison

PurpleAir Classic and PurpleAir Flex hourly data for PM2.5, temperature and relative humidity were compared by quarter to reference values (Q1: January-March, Q2: April-June, Q3: July-September, Q4: October-December).

PM2.5

Quarter 1

Quarter 2

Quarter 3

Quarter 4

Temperature

Quarter 1

Quarter 2

Quarter 3

Quarter 4

Relative Humidity

Quarter 1

Quarter 2

Quarter 3

Quarter 4

Correlation Comparison

PurpleAir Classic and Reference Correlation

PM2.5

Temperature

Relative Humidity

PurpleAir Flex and Reference Correlation

PM2.5

Temperature

Relative Humidity

PurpleAir Classic and PurpleAir Flex

PM2.5

Temperature

Relative Humidity

Results Summary